title: Evaluation of nonlinear frequency compression for school-age children with moderate to moderately severe hearing loss.
abstract: BACKGROUND
  Previous research has indicated that children with moderate hearing loss experience difficulty with recognition of high-frequency speech sounds, such as fricatives and affricates. Conventional behind-the-ear (BTE) amplification typically does not provide ample output in the high frequencies (4000 Hz and beyond) to ensure optimal audibility for these sounds.
  
  
  OBJECTIVE
  To evaluate nonlinear frequency compression (NLFC) as a means to improve speech recognition for children with moderate to moderately severe hearing loss.
  
  
  METHODS
  Within subject, crossover design with repeated measures across test conditions.
  
  
  METHODS
  Fifteen children, aged 5-13 yr, with moderate to moderately severe high-frequency sensorineural hearing loss were fitted with Phonak Nios, microsized, BTE hearing aids. These children were previous users of digital hearing aids and communicated via spoken language. Their speech and language abilities were age-appropriate.
  
  
  METHODS
  Aided thresholds and speech recognition in quiet and in noise were assessed after 6 wk of use with NLFC and 6 wk of use without NLFC. Participants were randomly assigned to counter-balanced groups so that eight participants began the first 6 wk trial with NLFC enabled and the other seven participants started with NLFC disabled. Then, the provision of NLFC was switched for the second 6 wk trial. Speech recognition in quiet was assessed via word recognition assessments with the University of Western Ontario (UWO) Plural Test and recognition of vowel-consonant-vowel nonsense syllables with the Phonak Logatome test. Speech recognition in noise was assessed by evaluating the signal-to-noise ratio in dB for 50% correct performance on the Bamford-Kowal-Bench Speech-in-Noise (BKB-SIN) test, an adaptive test of speech perception in a multitalker babble background.
  
  
  RESULTS
  Aided thresholds for high-frequency stimuli were significantly better when NLFC was enabled, and use of NLFC resulted in significantly better speech recognition in quiet for the UWO Plural Test and for the phonemes /d/ and /s/ on the Phonak Logatome test. There was not a statistically significant difference in performance on the BKB-SIN test between the NLFC enabled and disabled conditions.
  
  
  CONCLUSIONS
  These results indicate that NLFC improves audibility for and recognition of high-frequency speech sounds for children with moderate to moderately severe hearing loss in quiet listening situations.
authors.affiliation: Hearts for Hearing, Oklahoma City, OK, USA. jace.wolfe@heartsforhearing.org
authors.forename: Jace
authors.initials: J
authors.lastname: Wolfe
authors.forename: Andrew
authors.initials: A
authors.lastname: John
authors.forename: Erin
authors.initials: E
authors.lastname: Schafer
authors.forename: Myriel
authors.initials: M
authors.lastname: Nyffeler
authors.forename: Michael
authors.initials: M
authors.lastname: Boretzki
authors.forename: Teresa
authors.initials: T
authors.lastname: Caraway
mesh_terms: D000293:Adolescent; D016477:Artifacts; D001309:Auditory Threshold; D002648:Child; D002675:Child, Preschool; D018592:Cross-Over Studies; D006310:Hearing Aids; D034381:Hearing Loss / Q000628:therapy*; D006801:Humans; D017711:Nonlinear Dynamics; D010700:Phonetics; D010898:Pitch Perception; D012720:Severity of Illness Index; D013067:Speech Perception